This article originally appeared in Crane Hot Line.
Many buyers looking for a new hydraulic swivel/slip ring combination unit have an objective of saving money and creating an assembly that surpasses the requirements of the application but is not over-engineered. There are three main styles of slip ring and hydraulic swivel combination units. Below is a look at each combination and their pros and cons.
These combo units integrate the slip ring directly into the end of the hydraulic swivel. Externally, the unit looks to be just a hydraulic swivel with the telltale signs of an electrical harness coming out both ends. The style is best used with minimal slip ring circuits and a critical requirement for sealing and protecting the slip ring components. It is commonly used in the forestry industry and military.
On semi-integrated combination units, the slip ring is mounted directly onto the end of a hydraulic swivel. However, the slip ring circuits are enclosed using a standard spun aluminum cover and not the swivel housing, like the fully integrated version.
This version is best suited for applications that have more slip ring circuits and less harsh requirements for sealing and protecting the electrical circuits, as well as designs with length restraints. The style is commonly used in the construction and railroad industries.
Combination units with a separated design have the hydraulic swivel and slip ring separated by a mounting tube and flange. This is the classic style that has been used for decades. The two units can be separated easily, and this style has the lowest heat transfer between the slip ring and swivel.
The separated design is best suited for applications with many slip ring circuits, low sealing, and protection requirements, as well as no stringent length requirements. This style also requires the least amount of upfront design work, so it’s well suited for low yearly requirements – for example, less than 10 per year. The style is also commonly used in the construction and railroad industries.
Brady Haugo is a Senior Design Engineer at United Equipment Accessories.